#include<stdio.h>
#include <stdlib.h>


int func;
int main(){
    

    printf("*******************************************\n");
    printf("                                           \n");
    printf("        this is a demo                     \n");
    printf("        name : Li GuoYi                    \n");
    printf("        email :linzhenhai6688@163.com      \n");
    printf("                                           \n");
    printf("*******************************************\n");
    printf("\n");
    printf("\n");
    
    while(1){
        printf("Perform basic/special functions,enter 'A/S'!\r\n");
        func = getchar();
    
    
    }
   
    return 0;  
}